1. Field of the Invention
The present invention relates to linearizing reactance sensor circuitry and more particularly to capacitance transducers for measuring pressure.
2. Prior Art
Practical reactance sensors commonly exhibit transfer functions that can be approximated by: EQU O=MX+NX.sup.2 +QX.sup.3
where:
O=output signal PA1 X=sensed variable PA1 M=sensitivity constant PA1 N=second order nonlinearity constant and PA1 Q=third order nonlinearity constant
It is desired that N and Q be as low as possible to give a desired linear relationship between the output signal, O, and the sensed variable, X. Prior art circuitry allows the third order constant, Q, to be adjusted as desired to minimize the combined effect of the second order term, N, and the third order term, Q. In the present invention substantially in dependent adjustment of the second and third order nonlinearity constants, N and Q, is made possible, resulting in substantially improved performance.